Culture Clash
by The Daleks' Advocate
Summary: Landing in 1968, the Doctor and her friends discover the sinister truth David Vincent had known for years: Ruthless aliens are infiltrating humanity to take over the Earth. Can the time travellers' optimistic approach bring hope where there is none? Or will they be swept into David Vincent's nightmare world? "The Invaders" canon characters: David Vincent
1. Prologue

**[This fic was inspired by the AO3 collection** ** _Doctor Who Crossover Christmas Challenge_** **, a year too late.]**

David Vincent ran frantically through the forest, his blue eyes darting left and right for a hiding spot or an opportunity to turn the tables on his pursuer. As gunshots cracked behind him, he stumbled and fell, but quickly scrambled back to his feet and redoubled his efforts to evade his enemy.

* * *

Out of place between trees sat a blue British police box. A bit further away, the Doctor, Yasmin Khan, Ryan Sinclair and Graham O'Brien strolled through the woods, taking in their surroundings.

"Fifty years in the past, USA, Vermont. A forest near a town called Essex Junction," the Doctor was saying.

"Fifty years, exactly?" Graham asked. "Is today supposed to be an anniversary or something?"

The tall blonde woman smiled. "Not that I know of. But you know the Tardis, she has a mind of her own."

"1968, that's the year Martin Luther King was assassinated," Yas pointed out. "There was still a lot of racism. Do you think Krasko's at it again?"

"Doubt it," the Doctor answered, shaking her head. "Nothing special happens in Essex Junction in autumn 1968."

Ryan's warning interrupted their reflections: "Guys, gunshots." He pointed towards a steep slope going up ahead of them. "Coming from over there."

* * *

David was forced to slow down when he reached a drop before him, and he dashed behind a bush, the only cover he could find. His pursuer soon reached the position, gun in hand. As he was distracted by the voices coming from downwards, David leapt at him and threw a solid punch.

The man let out a groan of pain but raised his gun again. With the experience born from years of fighting and the rage of survival, David grabbed his arm and forced it around. The struggle was brief until, in the confusion of the fray, the gun went off and hit its owner in the chest. David immediately let go; mortally wounded, his opponent stumbled back and fell down the slope.

Before the dumbfounded eyes of the four travellers, the man glowed an incandescent red and burned up, and after a few seconds, only a discreet scorch mark on the soil remained.

"What was _that_ ," Yas voiced what they were all thinking.


	2. Act I

**[For those of you who don't know** _ **The Invaders**_ **, the opening credits and narration are available on YouTube (no link, sorry, FFNet is being difficult). The guest stars in this fanfic would, obviously, be Jodie Whittaker, Tosin Cole, Mandip Gill and Bradley Walsh, plus whoever would play the lead alien (we can keep Frank Overton).]**

 _After two years of fighting the alien invader, an unexpected encounter leads David Vincent to an ally the likes of he's never met. An ally, from another time and another planet. An ally, who rejects guns and believes in giving everyone a chance –no matter who or what they are. An ally, whose very presence could upset the balance of the war._

David ran a cool, inquisitive gaze over the four strangers. They were unusual to say the least, particularly the blonde woman with the peculiar fashion sense. But even the two young people and the old man didn't look nearly as spooked as they should after witnessing the death and subsequent incineration of one of the aliens. The four Britons, as their accents had already hinted, were both understandably surprised, and suspiciously accepting of what they'd seen. At least, their conspicuousness probably ruled out them being aliens.

The blonde woman responded to David's peering with a smile. "Hello, I'm the Doctor, and these are my friends: Yasmin, Ryan and Graham," she introduced herself and the dark-skinned girl, the black young man and the old white man in turn. "And you are…?"

"David Vincent." He cautiously climbed down the slope to join them. He heard, briefly, a buzzing sound coming from the strangers, but by the time he looked up, there was nothing abnormal to be seen.

The Doctor tilted her head and shot the vague traces of ash a look. "Why was that man after you?"

"He wasn't a man," he replied grimly. "He was an alien. That's what you saw: They burn up when they die on Earth."

"Man or alien, why was he trying to kill you?" Graham insisted.

"Because I was onto him." They'd seen the alien's death; David might as well present the full situation and, hopefully, gain allies. At least, they wouldn't disbelieve his words out of hand. "You can spot some of them from an anomaly of their hand," he explained, illustrating by closing his fist but for the little finger, which he let stick out at an angle. "They also have no blood, and no heartbeat or pulse."

"And let me guess: They aren't friendly," Ryan commented with a disenchanted sigh.

David shot him a humourless look. "They want to take over the Earth, and we're in the way. They plan to wipe us out to get it."

Yaz looked at him thoughtfully. "You've been fighting them for a long time, haven't you?"

For the first time since the travellers had met him, wariness showed in his eyes. He lit up a cigarette and took a puff before finally answering: "Two years. I can't stop until either we drive them out or they win."

In the back, the Doctor pushed away dark memories of her own. "Well then, team," she announced perkily, "shall we go alien-hunting?"

* * *

The group sat in the diner where David had noticed the alien, a town map spread out on the table between them. "We're here," he explained, pointing on the map as he spoke, "and I followed him all the way to there. That's where he tried to ambush me. But it may not be significant, he could've noticed me from the start and purposely led me into a trap."

"What of the guy he was having a drink with?" Ryan asked. "Is he another alien?"

"I don't know." That was what made the situation so hard. All too often, you couldn't tell the aliens apart until it was too late. "He could just have been part of his cover."

Yaz looked around. The place itself, at least, looked mundane enough. "Have you got any idea what the aliens want in Essex Junction?"

"Could be anything," David shrugged. "Pushing one of their own to an official position, building a weapon, coordinating their new arrivals… They could just happen to have a regeneration station nearby."

The Doctor whipped her head towards David. "'Regeneration'?" she echoed quizzically.

"Oxygen's toxic to them. They need to regenerate themselves regularly or they die."

"Ah," the Doctor nodded. "I see. Please go on," she said, eager to distract him from her initial reaction to the word.

Graham tapped his finger at a spot on the other side of town. "It says that's an Air Force training base; looks like a likely target."

"There's also this big area, and it's much closer to the diner," Yaz pointed out, showing another point on the map. "Do you know what it is?"

"A semiconductor plant," David answered, elaborating, as if they might not know what it meant, "They make computer chips."

The time travellers exchanged a look.

"I think we should pay them a visit," the Doctor said.

* * *

David stopped the time travellers before they neared the plant's entrance. "Wait for me here while I get a quick first look around," he instructed them without leaving room for discussion. "I have a better chance of remaining unnoticed on my own."

As soon as he'd walked away, the Doctor leaned forward to warn her friends in a low voice, "Remember, this is the past. We must be careful."

"Well, we know aliens didn't take over the Earth in 1968," Graham remarked. "So we _can_ stop them, right?"

She pulled an oblong device out of her pocket to take a quick reading –the object buzzing like the sound David had heard earlier– before answering. "These aliens aren't time travellers. They belong to this time. So yes to stopping them here and now, but we can't help David expose them publicly either because I know for certain the Earth military doesn't learn of them." She scanned the area again and groaned in frustration. "Too much interference," she sighed.

David soon returned. "I didn't see anything suspicious," he explained. "We need to get in. Usually, I'd pretend I'm looking for work." He ran his eyes over the odd group, doubtful.

"No worries," the Doctor interrupted with a grin, "I have easy access anywhere. Come along, gang."

She strolled to the entrance and flashed some kind of credentials in front of the watchman, quickly pulling the card back out of view. David narrowed his eyes. This didn't look natural at all; but apparently, it worked, and the watchman nodded, clearly intimidated, and opened the gate. "Of course, Mrs Smith. Should I inform the director of your coming?"

"Nah," the Doctor answered, "we'll find our way." As they all walked in, David already strolling to the building before them, she peeped at the card she'd shown the watchman. "Apparently, I'm head of the parent company's internal security services," she told her friends, always amused at what the psychic paper made her out to be.

* * *

Behind the reception desk, a young woman greeted the newcomers with a smile. "What can I do for you?"

The Doctor decided to go along with her assumed identity, and showed the psychic paper to the woman quickly. "We'll need to talk with your director but first, we'll have a look around."

"Has there been any significant change at the plant recently?" David enquired.

"How recently? The former director died of a heart attack five months ago, but surely you already know that?" the receptionist answered. "Other than that, not that I can tell, no."

After thanking her, the Doctor turned to David and asked quietly, "You think he was murdered?"

"Likely," he confirmed. "A heart attack's what happens to us in their regeneration tubes."

Although there was no dearth of people around, none of them was able to tell more than the receptionist. After questioning half a dozen employees, David and the time travellers still had no lead besides the new director, Mr Hughes. But if he was an alien, they had to learn everything they could before confronting him.

For the moment, their questions were aimed at a young engineer named Charles Collins. "And who would you be again?" he asked, casting a perplexed gaze over the mismatched group.

"Internal security services," the Doctor answered, whipping the psychic paper in front of his eyes.

Charles frowned. "Okay… Sure, I'll do whatever I can to help. What brings you to the Essex plant?"

David was the one to explain, "We have reasons to suspect insider contact with a foreign hostile power."

The young engineer nodded and eyed them in turn again, silent, surprised, and perhaps a bit disbelieving.

"Have you noticed anything out of the ordinary lately?" Yaz elaborated.

"Especially around or after the previous director's death," Ryan added.

Charles stayed silent for a moment, deep in thought, before shaking his head. "I'm sorry, nothing comes to mind. Have you spoken to the new director, Mr Hughes?"

"We will," the Doctor assured. "We wanted to talk to the workforce base first."

"Did his appointment coincide with other new arrivals?" David asked.

Charles shrugged. "Not particularly. But a lot of people come to work at the plant: We're expanding rapidly. I've been here less than a year myself."

"What about the semiconductors themselves?" Graham tried. "Anything worth of note in the last months?"

The engineer chuckled. "That's hardly news; we're developing faster and better processors all the time! You know we're the best microchip plant in the entire country, possibly the entire world. Nothing can beat what comes out of these walls," he concluded proudly.

The Doctor nodded thoughtfully. "Thank you, Charles."

"If there's anything I can do, I'll be glad to help," he smiled before leaving them.

She turned back to her companions: "I'll have to get a look at the research wing at some point. For now, let's continue asking around."

* * *

As soon as he'd walked out of view, Charles Collins took out a small device, roughly shaped like a half egg, its fat surface lighting up as he spoke into it: "There's a group of five people who've come to the plant and are asking questions. One of them at least may not be from this planet."


	3. Act II

While their friends were questioning yet another employee, Graham took Ryan aside. "Are you alright?" he asked with concern. "You've been awfully quiet lately."

"Yeah," the young black man sighed. "Just…" He hesitated, prepared to give a mundane noncommittal answer, then decided otherwise and spoke his mind: "This may not be Montgomery 1955, I still feel like everybody's giving me and Yaz odd looks. Like we don't belong here, or with the rest of you."

Graham nodded, sympathetic. Despite being a white man himself, having been married to Ryan's grandmother made him more acutely aware of racism than most of his peers. "Wanna get some fresh air?"

"Yeah," Ryan nodded.

* * *

Fresh air and a stroll on the factory's grounds, indeed, did Ryan some good. As he and Graham were about to return to their companions, a young woman approached them. "Excuse me? I've heard you ask questions about anything unusual? There's something you should see."

"What is it, Miss?" Graham asked.

The woman shook her head in apologetic ignorance. "I'm not sure how to describe it… Some kind of machine, I think, but it looks like nothing I've ever seen. It's in one of the cars. You should have a look yourselves."

She led them to the parking lot. "There, on the backseat," she told them, pointing to a sedan.

Intrigued, Graham and Ryan leaned forwards to peer into the vehicle –but they weren't given the chance to realise it was actually empty. Two men came out of their hiding place behind a van and, taking the time travellers by surprise, knocked them out and shoved them into the car.

The two assailants and the woman sat in and promptly drove off with their booty.

* * *

Still in the plant's entrance hall with the Doctor and David, Yaz looked around, a frown on her brow. She took out her phone out of habit before chuckling at the _no signal_ message. Of course. Mobile coverage left much to be desired in 1968. Putting it back into her pocket, she turned to the Doctor. "Doctor… Have you seen Ryan and Graham? They've been gone a while."

Searching the room with her gaze, the Doctor's face soon mirrored her friend's concern. "They went outside earlier," she answered. "But I haven't seen them come back."

As for David, his usually surly expression became even grimmer. "We'd better check on them."

After exiting the building, searching for their friends and calling out for them for a few minutes, it became clear they weren't on the compound anymore.

The Doctor looked to her two companions sternly. "Yaz, David, continue trying to find out more at the plant. I'll be looking for Ryan and Graham," she instructed. "It's about time I have a word with these aliens."

* * *

Graham woke up with a strong headache. Ryan was already conscious, struggling against the bonds tying him to his chair and glaring at their captors. Sitting at a desk, a man in a suit was examining Ryan's phone with interest; two guards clothed in identical dark blue-green coveralls watched over the prisoners with a ruthless air.

"Sir, they're awake," one of them informed his superior.

The man stood up and held out the phone. "Interesting device you have here," he said with an expression that could have been amusement. "I presume this is some kind of communicator."

His smugness only redoubled Ryan's attempts to free himself. "Release us!" he growled.

The alien let out a small laugh. Humans always reacted so emotionally. Without losing his air of slightly mocking confidence, he put the cell phone back on the desk. "I'm afraid you are in no position to make demands." He went on, "My name's William Myers, and I'm very curious about you and your friends."

"You picked the wrong guy to mess with, mate! We won't tell you anything!" the young man retorted.

William chuckled again. "Oh, yes, you will," he announced ominously. He nodded curtly to one of the guards, who went behind Ryan to hold his head and force him to look forward, and he took out a device like two crystals joined at their tip. Holding it gently between two fingers, he raised it before Ryan's eyes; the object started spinning on its axis and lit up, projecting changing pastel colours on the young man's face.

Graham's stomach churned with worry. "What are you doing to him?! Leave him alone! Whatever you're doing, do it on me instead!"

William ignored him to keep his attention on Ryan. "Who are you?" he asked in a calm, firm voice.

Feeling his will erode, Ryan tried to avert his gaze, but the guard was holding him firmly.

"Who are you?" the lead alien repeated.

The hypnotic control broke through Ryan's resistance. "Ryan… Sinclair."

"And the others?"

"Graham O'Brien. Yasmin Khan, the Doctor. David Vincent."

The aliens exchanged a glance.

"The first four of you are aliens," William stated.

"No… only the Doctor," Ryan admitted despite himself.

Graham could only watch helplessly, sick with anguish. What if the effects were permanent? He couldn't bear losing him!

"What planet does she come from?" the alien continued.

"I don't know… She hasn't told us." At this point, Ryan was fully subjected to the crystal's hypnotic pull, and the guard released his head.

"Are there others of her people on Earth?"

"No, I don't think so."

"And what is _she_ doing on this planet?"

"I think she just likes Earth and humans," the young man hazarded.

"So it had nothing to do with us?"

This time, Ryan's answer wasn't hesitating. "No. We didn't know about you until we met David."

"What kind of weapons does she use?"

"The Doctor doesn't do weapons. She hates guns."

William switched off the trance-inducing crystal with a satisfied smile. "Thank you, Mr Sinclair," he said in what, given the circumstances, had to be irony, "this was very informative." Without further attention to the prisoners or the cell phone, he left the room, followed by his two subordinates.

Slowly regaining his senses, Ryan shook his head and blinked twice to dispel the mists of hypnosis.

"Are you alright, son?" Graham asked kindly.

"I–I think so," he nodded slowly. He averted his gaze in shame. "I'm sorry. I couldn't stop myself from talking."

"Not your fault. You did what you could," his step-grandfather tried to comfort him.

* * *

"Do you think Ryan and Graham are alright?" Yaz asked David with a lump of worry in her throat.

"If the aliens wanted them dead, we'd have found their bodies," he asserted.

She nodded, forcing herself to believe his assurance. The Doctor would find and rescue them. Yaz trusted her friend. She'd save them! Partly to distract herself through their task, the young woman looked to David: "I don't think we'll learn more here; we should go see Mr Hughes."

"Yes," he agreed. "Stay on your guard: Even if he isn't one of _them_ himself, he may be working for them."

She frowned in confusion. "Wait, didn't you say the aliens want to destroy humanity? Why would anyone help them willingly?"

"Greed. Power. They know how to promise what people want to hear."

They made their way to the right floor without trouble. Before they reached Mr Hughes's office, though, David suddenly grabbed her by the arm without a warning when someone exited a room, and hurriedly led her around a corner. The man locked the door behind himself and started walking off.

"That's the man I saw with the alien in the diner," David whispered.

"You don't want to confront to him, then?" Yaz asked in the same voice.

"Not before we search the room. I want to find what we can before he knows we're onto him."

They waited a few moments to let their suspect disappear into an elevator and, with a glance around, went to the door –the plaque read _Vice-director, Thomas Brown_. The lock was fairly standard and soon enough, David had picked it and the two of them could sneak in.

* * *

Once alone, the Doctor took out her oblong sonic device again and scanned the parking lot. It wasn't long until the two men who'd abducted Ryan and Graham came back in their car; following her readings, the time traveller caught up with them just as they'd parked and stepped out.

"Oi! Aliens!" she called them.

Unflinching, they both raised guns and trained them on her. "Doctor, if you'd care to come with us," one of them ordered in a tone as polite as it was uncompromising.

"And I was just about to say, 'take me to your leader'," the Doctor commented wryly.


	4. Act III

In Thomas Brown's office, Yaz sifted through the lockers David had just forced open while he turned his attention to the desk drawer. The illegality of it all made her a bit uneasy, although in fairness… Well, it wasn't like the Doctor herself would be above it; she merely had a more convenient tool to open locks.

So far, Yaz had only found expected documents for the normal workings of a semiconductor factory, from technical reports to business plans to personnel files to analyses on the competition. David's first examination of the drawer didn't reveal anything of use either, but he soon noticed it seemed too shallow. With a grunt of effort, he managed to lever out the false bottom.

"Yasmin," he called in a hushed voice. She came over to see what he'd found: In the hidden compartment lay a hand-written note with the address of what appeared to be a shipping company, as well as a large envelope. Within it, they discovered detailed instructions on how to add an obviously foreign component to the mass production of computer chips.

They exchanged a look. Now they were getting somewhere.

* * *

Under the constant thread of the second alien's gun, the Doctor was driven to the shipping company's large warehouse. She had no intention of escaping, however; what better way to confront the enemy than to let herself be brought to their leader? Not to mention there was a chance Ryan and Graham were kept somewhere there too.

Her captors dragged her out of the car and into an office. As they entered, William stood up from the chair he'd been sitting in.

"Doctor, it's a pleasure to meet you. I'm William Myers. Please excuse my people's roughness, we weren't sure you'd come willingly."

The Doctor ignored his display of friendliness. For once, a dangerous glint was dancing in her pupils. "Where are my friends?" she demanded in a deceptively calm tone.

"They're unharmed, and they will remain so as long as you cooperate." As the answer reassured her somewhat, he looked at her thoughtfully. "Why are you so invested in this planet's people, Doctor? They're primitive, irrational and violent. They'll sell their own future for money and power. What is there in this world that entices you so much?"

"They're not perfect," she admitted reluctantly, "but they're capable of great things too. Altruism, love, courage, sacrifice… They're just as human as fear and greed and ambition. They'll learn better ways, eventually. You've got to give them time."

"I'm afraid it's a luxury they won't have," he shrugged. "We have other plans."

She narrowed her eyes. "This is your only warning, William Myers. Leave this planet in peace or I'll stop you."

"By yourself?" William retorted. "Mr Sinclair said you're alone on Earth."

"I'm not alone when I have my friends. My _human_ friends."

He shook his head pensively. "Really, Doctor, I don't understand your faith in them. It's true Mr Vincent has been a thorn in our side for years, but that doesn't make them any more reliable." After a second, he let out a sigh with a shrug. "But suit yourself. You can't stop us anyway. Even if you happen to win here, our people will simply come up with another plan."

At these words, he exited the room, leaving the Doctor with her two abductors.

* * *

The sound of a key in the lock made Yaz jump and whip around, while David ran to hide behind the door, poised to attack the newcomer. Thomas Brown soon came in cautiously and set cold eyes on the time traveller.

"Miss Khan. Did–" he began with a slight sneer; but he never got to finish his sentence: David leapt out of his hiding place and threw a solid punch into his stomach, followed by another on his head. With a groan, Thomas fell to the ground, inert.

Yaz rushed forward to check on the unconscious man –or alien–; as she crouched down beside him, David grabbed her roughly by the wrist to force her back up. "We need to go," he urged.

The young woman angrily yanked her arm free. "Don't do that again," she threatened. "I want to check on him first."

"He's fine," he retorted. "If he'd died, he'd have burned up."

"You're not even certain he is an alien!"

In response, David strode to the desk, took a paper knife and returned to Thomas to make a gash into his finger. He raised the hand for Yaz to see the clean wound. "No blood," he stated. "Not even a trace." Dropping the knife to the floor, he stood and walked to the door.

Yaz followed with a last sorry glance to the alien and a long sigh.

* * *

William returned to the cell where Ryan and Graham were held captive, a friendly expression plastered on his face. "Mr Sinclair. Mr O'Brien," he greeted them. As the young man started struggling against his bonds again, the alien raised a placating hand. "Please, please, do calm down," he requested. "I feel we've started on the wrong foot. But maybe we could help each other."

"We don't need your help," Ryan snapped back.

"Also, maybe you should release us first," Graham pointed out with a hint of sarcasm.

"I will, once we've reached an agreement," William answered calmly. He looked Ryan pointedly into the eyes. "As a black man, how much do you enjoy the current state of affairs, Ryan? Even if Britain isn't this country, I know what people like you are going through on a daily basis."

Ryan jeered, "Says the white dude in a suit."

"Ah, but the human form is only a pretence. We exploit human prejudice to our advantage, we neither cause nor approve of it," the alien corrected. "I'm offering you a world where you won't have to bow down before the rest of your people ever again."

"A world where all humans will live under your boot no matter what skin colour," Graham scoffed. "If we're even allowed to live."

"It doesn't need to be. Work with us, and you'll be granted the power to shape the world as you see fit."

"That's what you don't get, mate," Ryan replied. "We're not interested in power. Yeah, I'd like to live in a world where I won't feel constantly put down. But that's the thing: It's not what you're offering. I won't get it with aliens or anyone else becoming the new masters. I met Rosa Parks and Martin Luther King," he said with a burning light of hope and pride and humility in his eye. "They're the ones who can bring up the world I dream of. People who stand proudly for what they believe in –not people who deceive, and kidnap, and kill."

William's expression became colder as he straightened up. "Very well, if that's your choice." He turned to Ryan's grandfather: "What about you, Graham? Are you a more reasonable man?"

The old man's gaze clouded over. "You can't give me what I want more than anything else," he answered sombrely. "And even if you could, she wouldn't want me to betray the human race for her. Especially not after giving her life to protect people from other aliens who thought they could use Earth as their plaything."

William didn't bother to answer. He kept his eyes on Graham for a second before turning heels and leaving the two prisoners alone again.

* * *

With the warehouse their best option for rescuing Ryan and Graham, David led Yaz back to his car. After checking the gun he'd kept from the ambush earlier that day and refilling the barrel, he took a second one from the glove compartment and handed it to his companion. "Can you use a gun?"

The young woman stared at the weapon, hesitant. "I'm a trained police officer," she explained. "But I've never shot anybody and I'd rather not start today." Even in self-defence, she wasn't entirely sure she could –let alone attacking potentially unarmed aliens in cold blood.

More irritated than moved by her reluctance, David shoved the second gun into her hands. "If you hesitate, _they_ won't. You want a chance to save your friends? Take the gun, and keep ready to use it."

After second of inner debate, she sighed and finally relented. The Doctor wouldn't like it, but even without harming anyone, human or otherwise, Yaz could always fire in the air or at some piece of equipment. She really hoped the aliens would be open to compromise without having to resort to threats, though.

Still, seeing how ruthlessly David had reacted with Thomas Brown, as actual as the danger was, she wondered whether, perhaps, he was actually making things worse. "Have you ever tried talking to them peacefully?" she asked. "We don't even know what they truly want with the chips."

He cast her a cold look. "I've been too busy fighting for my life and all of humanity," he replied curtly before sitting at the wheel. "And we already know what they want: The Earth for themselves." And human beings happened to be in the way.

Yaz tilted her head. "Why are they even so determined? You said yourself our atmosphere's toxic to them. Earth doesn't sound like it'd be their first choice to begin with."

"I don't know, and I don't care. I'm only interested in making them leave us in peace once and for all," he answered in a tone leaving no room for further discussion.

* * *

The Doctor had waited for an opportunity, trying to engage the conversation with her guards or to confuse them with twaddle and subject jumps; but these people were ridiculously hard to distract, and only silent stares had given any indication they even heard her.

Her opening came when William's return caught the guards' attention. Much faster than a human, she leapt forward and flung her fingers at a very specific spot on the nearest alien's throat… only to realise the Venusian hold had no effect on him.

But even if it hadn't paralysed him as she'd expected, her quickness had taken her opponents by surprise. She hurled him at the other two, and dashed out of the room.

By the time the three aliens reacted and rushed after her, the Doctor was nowhere to be seen in the corridor.

* * *

David and Yaz spent the thankfully brief trip to the warehouse in tense silence. Large enough to house several buildings, the enclosure was fenced with barbed wire, but security appeared rather mundane. Presumably, the aliens relied on discretion and thought the best defence was to appear unimportant. Yaz wondered again whether there was more to them than the obvious invasion.

The duo found an entry point in the form of a loose fencing. David lifted it for the young woman to crawl under, then was briefly surprised when she returned the favour to ease his own passage. All his thoughts soon returned to the enemy, however, and he ran to the nearest wall, Yaz on his heels.

Peering through a dirty window only showed innocent-looking crates, so they sneaked towards the next building. This time, they discovered what they were looking for: Inside a large room, a group of people in dark blue-green coveralls busied themselves around metallic machines covered in buttons and dials. On one of the devices, a screen displayed what the time traveller recognised as the blueprint for an electronic chip, albeit of a distinctly alien design.


	5. Act IV

Loud voices and the sound of quick steps in the corridor informed Ryan and Graham the Doctor was loose somewhere in the place. One of the guards in blue-green coveralls opened the door to their cell and peered inside to check on the prisoners.

"The Doctor's giving you trouble?" Graham taunted, still resentful for the hypnotic interrogation his step-grandson had been subjected to.

"You'd better listen to her," Ryan added. "She's stopped meaner and badder than you."

The alien ignored them; just as he closed the door, he heard clattering in a storeroom. Gun at the ready, he turned on the light switch and cautiously stepped in… only for the door to slam behind him and the lock to fuse shut.

The Doctor quickly went to free her friends, sonic device in hand and a grin on her lips.

"Doctor, I'm so glad to see you. Hospitality here is terrible," Graham joked while she untied them.

"Where are Yaz and David?" Ryan worried, grabbing his phone from the table. _Communicator,_ ha.

"Still investigating the factory, normally," she reassured him. "I left them to look for you. I didn't want David to see the sonic." Showing her distinctly non-terrestrial technology to him hadn't seemed a judicious idea… As they passed the storeroom with the trapped alien banging on the door, she urged them to move fast: "Won't keep him long," she warned.

* * *

"We should get going. Look for Ryan and Graham," Yaz whispered to David.

He nodded his agreement. Whatever the aliens were doing here didn't appear to be an immediate threat, and the two men were in danger as long as they were at the enemy's hands. With any luck, they were kept in a nearby building.

For lack of a better lead, they set to explore all the buildings in hope of finding their captured friends, more than once being forced to hurriedly dart around a corner to avoid being spotted. It seemed the aliens were quite agitated. Had the Doctor come and disrupted their sense of safety? Anyway, David noted phones in various corridors. Once the others were out of danger, it would be useful to call in the authorities and expose the aliens once and for all.

* * *

After running out of the building, the Doctor, Ryan and Graham hid among parked vans, taking the time for the blonde woman to check energy readings on her sonic device. "Lots of alien equipment over there," she said, pointing to the warehouse in which David and Yaz had seen workers make computer chips earlier.

A couple of minutes later, the trio peered through the very same window, unaware their friends had preceded them and were actually looking for them in another building.

"What do you reckon they're doing, Doc?" Graham asked.

"They're preparing add-ons to bug the chips from the factory, I think," she guessed.

Ryan frowned at the sight of the aliens' devices. "Is it me, or does all this stuff look… simple?"

The Doctor shook her head. "It's not you," she confirmed. "Twenty-first century tech could do better. Even your own cellphone's more complex."

She gazed at the aliens, thoughtful, when William's voice made the three of them jump and whip around: "Doctor, Mr Sinclair, Mr O'Brien. I see you're admiring our workshop, but I'm afraid I'll have to interrupt your contemplation and ask you to come with us." He was flanked with the two abductors dressed as humans and a guard in the usual blue-green coveralls, all three of them pointing guns at the time travellers.

The Doctor, Ryan and Graham followed the aliens back to the cell and let themselves be tied up.

"Getting captured is a habit I'm not fond of developing," the old man half-joked with a sigh.

The Doctor cast an intense look at the leader of their captors. "Why are you after the Earth, truly?" she asked. "I've seen a lot of wannabe alien invaders in my lives, and I can tell you're different. Desperate. I've been blind not to see it earlier –how a single man could've been able to hold you back for years."

As William opened his mouth to stop her train of thoughts before she guessed too much, she interrupted him: "You don't have a choice, do you? You're not conquerors, not really. You're refugees."

"That's no concern of yours," one of the two abductors snapped; but his superior silenced him with a glance and nodded to the Doctor.

"You're right, Doctor," William admitted. "Our planet is slowly dying. The more we delay, the more of our people perish. Earth merely happens to be the only inhabitable planet in range. You understand we can't back down."

"But then, why not come and _ask_ for their help, you know, _peacefully_? You're good at hiding, I give you that," –at least, they were to people who didn't have sonic scanning devices– "but you're terrible fighters and no offence, but from what I've seen, your technology isn't exactly cutting edge by most spacefaring species' standards."

The alien didn't bother answering, simply shaking his head with a mirthless laugh.

"Not everyone's a racist," Ryan spoke up, suspecting what was on his mind. "Some people _would_ help."

This time, William deigned respond with words: "Not enough. Not those who control the weapons your people are so fond of developing."

"Look," the Doctor insisted, "you can't just kill or enslave humanity either. It's still their planet. Leave the Earth alone, return home and send a call for help," she urged. "There are other, more advanced races out there. Races who can help you evacuate your people to safety."

"Is this the best you can offer, Doctor?" William asked sarcastically. "I don't think so. I have a better idea. We know this area of space and you aren't from any of the surrounding systems: You must have come from farther away than our own people have ever travelled. Give us access to your ship technology, and _if_ we can duplicate it, we'll leave and colonise another more hospitable planet."

The Doctor shook her head sadly. "I can't. I'm sorry, I simply can't," she apologised. "You'll have to find ways to save your people on your own."

The hard look William cast her did nothing to reassure her. "Well then, you'll forgive me for doing exactly that," he stated. He leaned forward threateningly. "You _will_ help us, Doctor. One way or another."

"I just said–"

He turned to one of his subordinates in human clothes: "Kill one of the humans. The old man." To the Doctor, he added, "Your young friend will be next, unless of course you prove more cooperative."

"No!" she shouted, eyes flashing in a mixture of worry and anger.

A shiver ran down Graham's spine. "Maybe we can talk about this…" he pleaded.

" _Touch him and you're dead!_ " Ryan roared as as the other alien approached a lit-up disc device from his grandfather's neck.

The Doctor opened her mouth to speak but before she had time to utter a sound, the door burst open to reveal Yaz and David. The young police officer pointed her gun at the alien with the disc: "Stop! Move away from him!" she ordered.

Her companion, however, didn't bother giving threats. He fired in rapid succession at the armed alien, the coveralls-clad guard and William, and they fell one after the other, clutching their injury as they glowed red and incinerated. Their last compatriot tried to run away, only to barely reach the corridor before David's bullet hit him in the back and ended his life.

A shocked silence fell on the scene, only disturbed by the sound of Yaz's dropped gun clattering on the floor. After several seconds, the Doctor got out of her ropes, stood up and strode to David, cold anger in her voice: "You didn't have to do that. I could've talked them down!"

"I know how they work," he replied curtly. "Maybe you could –and then they'd have eliminated you the moment they didn't need you any more." With the immediate threat dealt with, he left his infuriatingly meek allies and returned to a phone in the corridor.

Glancing around cautiously to make sure the gunshots hadn't attracted attention, he called the operator and was soon put in contact with a Major at the Air Force training base. "I know it'll be hard to believe but there's a major enemy operation underway in Essex Junction," he whispered urgently. He gave them the address of the warehouse, then stressed, "You need to send your men immediately before they realise they've been found out."

Unsurprisingly, the Major was unconvinced with David's claims. " _What kind of 'enemy operation'?_ " came the doubtful reply over the phone. " _I need something more solid before I send men on a wild goose chase to the other side of town._ "

"I can't give you details over the phone, but it has to do with semiconductors. You'll see with your own eyes when you come. But hurry before they have a chance to dispose of the evidence."

The officer sighed. " _Very well. Stay where you are, I'll send a detachment._ "

David hung up, not yet daring to hope his years-long quest to expose the aliens would end at last.

* * *

As the Doctor, Yaz, Ryan and Graham caught the end of David's phone call, they didn't need to speak to know what had to be done. With an urgent nod, the Doctor quickly led them to the building that served as the aliens' chip workshop. Concentrated as they were, the workers didn't immediately notice the intruders.

"Aliens, listen to me," the Doctor announced loudly. Startled, they interrupted their tasks to look at the time travellers and prepare to fight the threat. They certainly hadn't expected the warning that followed: "William Myers is dead," she went on, "and the human military's about to storm this place. If you want to remain free, you need to evacuate _now_."

Their reaction, however, caught her off-guard; after exchanging an alarmed look, one of them ran to a lever on the wall. The Doctor knew a self-destruct switch when she saw one. "No, don't!" she cried out, horrified at such a drastic measure.

In a split-second, she evaluated her chances of stopping the alien in time at slim to none. There was only one remaining option. " _Out!_ " she shouted, all but shoving her friends back through the door.

They barely made it outside before the entire building behind them glowed bright red and vaporised. The four time travellers slowly turned around and stared at the smoking, now vacant spot, painfully trying to process what had just happened.

"They destroyed the building… with themselves still inside…" Yaz said in a small, flinching voice. "Why would they do that?"

From a distance, David could only watch helplessly as the evidence literally vanished before his eyes once again.


	6. Epilogue

"You tipped them off," David accused angrily. "I had a chance to expose them once and for all, and _you tipped them off_."

"Have some decency, man," Ryan shot back, hiding his upset behind aggressiveness. "They're all dead."

David glared and stormed away without a further word. He lit up a cigarette, steeling himself for facing the soldiers about to arrive and, as always, passing for a phoney and a crackpot.

The Doctor watched his retreating figure in silence. She knew all too well what war could do to people, what it could turn them into. That didn't mean she liked it. With a mirthless smile, she nodded for her friends to follow her away from there.

* * *

The time travellers had too much on their minds to speak during the return trip. Not long before reaching the time ship disguised as a blue police box, they passed a strolling middle-aged couple, who saluted them politely. After the previous events, the forest seemed so deceptively peaceful. Life continued, they guessed. Did these aliens mourn their dead?

They walked into the Tardis in solemn silence. As the Doctor checked something on the console, Yaz closed the door behind herself with a thoughtful glance back. "What happens to them now?" she asked. "David and the aliens."

"Maybe we should go to their planet to help them," Graham suggested.

"Remember this is still fifty years in the past. We can't get involved too deeply," the Doctor warned. She continued fiddling with her systems for a moment before looking up from the screen to her friends. "David wins in the end even if he never manages to reveal their existence publicly," she informed them. "About a year from now, the aliens give up and leave the Earth."

The old man felt a twinge of compassion. "But they had nowhere else to go," he pointed out. Of course, he was glad they hadn't taken over, but he didn't want for them to perish, either.

The Doctor nodded in grim confirmation. "Most of their people die in the coming decades as their home planet becomes gradually more and more uninhabitable. But," she added in a more upbeat tone, "a few thousand of them survive on moons and other sterile places in nearby solar systems. Eventually the survivors are found and rescued by other aliens, and offered a new home to live on. In time, they recover, and they'll actually become quite prosperous in a couple of centuries. Shall we go and say hello?" she concluded.

With a chorus of vigorous nods welcoming the suggestion, she slammed the lever, a grin on her face, and the Tardis dematerialised.

* * *

In the forest, the couple of walkers paused and turned around when they heard a strange, eerie groaning noise. They went back to the clearing to realise the blue police box was somehow gone. As the woman passed a thoughtful arm around her husband's shoulders, her little finger stubbornly refused to bend along with the others.

 _While David Vincent returns to his lone, desperate fight against the invaders, the Doctor and her friends return to adventures where hope always eventually prevails. Two irreconcilable visions which, for a moment, tried to unite against a common foe. Two worlds further apart than David Vincent and his deadly enemy will ever be._

 **[** **I couldn't help but give the poor aliens an eventual happy ending of sorts. They aren't bad people, not really, just desperate people doing desperate things. Perhaps a bit arrogant too, but they actually have a point: Within the universe of the show, most humans** ** _are_** **selfish, greedy, power-hungry, narrow-minded people. Not to mention incredibly racist, as it's repeatedly emphasised the aliens are "** **beings"** **, "** **creatures"** **, "** **not (real) people"** **. The central plot point of one of the episodes is even that murder only means to kill another human being, not another** ** _person_** **, hence killing an alien is alright regardless of context!]**

* * *

 **[** _ **Doctor Who**_ **and** _ **The Invaders**_ **are such different shows, I hope I managed to strike an interesting balance. I also hope I managed to make this fic as understandable for people who don't know one of the shows as if its characters were simply one-off OCs, though the Doctor has so much baggage at odds with the** _ **Invaders**_ **universe I probably failed at least with her.]**


End file.
